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How do fossil fuels form and how are they extracted?

How do fossil fuels form and how are they extracted?. 1. What is oil?. 2. How does it form?. Oil ‘Black Gold’. 3. What rocks and structures is it f ound in?. 4 . How can geologists find it?. 5 . What are the problems with its e xtraction and use?. 1. What is oil?. C. C. C. C. C.

raphael-hardy
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How do fossil fuels form and how are they extracted?

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  1. How do fossil fuels form and how are they extracted?

  2. 1. What is oil? • 2. How does it form? Oil ‘Black Gold’ • 3. What rocks • and structures is it • found in? • 4. How can geologists find it? • 5. What are the problems with its • extraction and use?

  3. 1. What is oil? C C C C C C C C Hydrocarbon H • Oil and gas are made of a mixture of • different hydrocarbons. • As the name suggests these are largemolecules made up of hydrogenatoms attached to a chain of carbon • molecules. Crude Oil

  4. Petroleum Petra = Rock Oleum = Oil Contains: 1. Why it classed as a non -renewable resource? • Crude Oil (Liquid) 2. Why is petroleum sometimes called a fossil fuel? • Natural Gas (Gas) • Asphalt (Solid)

  5. What is oil (origin)? 10,000 of these bugs would fit on a pinhead! Plant plankton Animal plankton en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg • Most oil and gas starts life as microscopic organisms called • plankton that live in the ocean.

  6. 2. How does it form (Oil Formation) Anaerobic bacteria form saropel Die, Sink & Accumulate on SF Low energy & anoxic environment Plankton Further burial = compaction & inc. T. Burial to form fine grained shales. Further maturation Maturation to form kerogen Petroleum • When die sink in water column and accumulate on sea bed • Remains of microscopic plankton in ocean (Float on surface) • In a low energy anoxic environment (prevent breakage and decay) • Anaerobic bacteria produce partial decay to form organic mud called saropel • Burial, occur to cause fine grained organic rich source rock e.g. Shales • Further burial causes compaction and increase in temperature with depth • Oil maturation to form kerogen then petroleum (‘Oil Window’ 50-200oC)

  7. Source Rocks? E.g. Kimmeridge Clay, Dorset • Black organic rich fine grained shales • e.g. Kimmeridge Clay, Dorset

  8. 3. What rocks is it found in? Reservoir Rocks ‘Once formed oil migrates into reservoir rocks where it collects’ • Poorly cemented sandstones are good • reservoir rocks as is chalk and limestone Add labels to a sketch to explain why sandstone is such a good reservoir? Poorly cemented: Allows interconnectivity of grains Well sorted: > Porosity Well rounded increases porosity Highly Permeable: pores must be interconnected to allow migration and then extraction of oil and gas Porous: Large pores and higher porosity means more storage space

  9. 3. What rocks is it found in? Cap Rocks ‘’Need to be impermeable to stop the further migration of the oil and gas upwards and escaping / seeping out at surface’ Make a list of potential cap rocks • Fine grained sedimentary rocks e.g. • Clay, mudstone and Shale! • Crystalline Sedimentary e.g. Evaporites (Halite)

  10. 3. What Structures is it found in? Oil Traps ‘a trap is needed to allow the accumulation of economic quantities of hydrocarbons’ • 4 Types: • Unconformity • Fault • Salt dome • Anticline

  11. Oil and Gas are always horizontal • There must always be a: • Source rock • Reservoir rock • Cap rock • Structural Trap

  12. Sketch these for your notes

  13. Explanation of why oil collected: Explanation of why oil collected: B) Fault A) Anticline D) Unconformity Explanation of why oil collected: C) Salt Dome Explanation of why oil collected: Task: Label the source rock, cap rock and reservoir rock of each. Shade in colour the oil and gas Explain why the oil has collected in this type of trap

  14. Task: Label the source rock, cap rock and reservoir rocks Shade in colour 3 locations where may accumulate oil and gas

  15. UK Oil and Gas field Map Oil and Gas Gas Only

  16. 4. How can geologists find it? Seismic Surveys

  17. Salt dome Found Drill here!

  18. Gravity Surveys

  19. Exploration Drilling

  20. 5. What are the problems with its recovery and use? Recovery • Ecological impacts e.g. spills while drilling • e.g. Gulf of Mexico 2010. • Explosions and fires on rigs off shore • Spills during transport Use • Releases CO2 • Unsustainable (finite) • Which causes climate • change • Pollution (acid rain)

  21. 1. What is coal? • 2. How does it form? Coal • 3. What rocks • and structures is it • found associated with? • 4. How can geologists find it? • 5. What are the problems with its • extraction and use?

  22. How is coal formed? 1. Plant matter accumulates at the bottom of a body of water in a swamp.

  23. How is coal formed? 2. The plant matter is protected from oxidisation and biodegradation by mud or acidic water (anoxic conditions) http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

  24. How is coal formed? 3. Over time, the plant matter is changed by heat and pressure to create a solid material. http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

  25. How is coal formed? 4. The coal grade increases from peat to lignite to bituminous coal to anthracite with time, increased pressure and temperature. http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

  26. Coal Rank Comparison Increasing Rank Which type of coal do you think is the most desirable to mine for the energy Industry and why? Which type causes the lowest pollution?

  27. Where are the British Coalfields?

  28. Why was the South Wales Coalfield (Glamorgan) So important?

  29. 1. What type of fold structure has preserved the Upper coal measures of South Swansea? 2. Explain how this structure allowed important deposits to be preserved (use a sketch)

  30. Deep burrial Features of the formation of fossil fuels that make exploitation difficult Slow processes of fm. Widely dispersed and often inaccessible areas e.g. coal in Antarctica. Young lignite has low energy density. Young oil is viscous

  31. Explanation of why oil collected: Explanation of why oil collected: B) Fault A) Anticline D) Unconformity Explanation of why oil collected: C) Salt Dome Explanation of why oil collected: Task: Label the source rock, cap rock and reservoir rock of each. Shade in / colour in the oil and gas Explain why the oil has collected in this type of trap

  32. Task: Label the source rock, cap rock and reservoir rocks Shade in colour 3 locations where may accumulate oil and gas

  33. Oil Formation Petroleum Options • Anaerobic bacteria produce partial decay to form organic mud called saropel • In a low energy anoxic environment (prevent breakage and decay) • Further burial causes compaction and increase in temperature with depth • Burial, occur to cause fine grained organic rich source rock e.g. Shales • When die sink in water column and accumulate on sea bed • Remains of microscopic plankton in ocean (Float on surface) • Oil maturation to form kerogen then petroleum (‘Oil Window’ 50-200oC)

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